====== zmap_GetScanlinePtr ======

===== Description =====

Get the pointer to the first pixel of a scanline in a map. 

===== Files =====

^ Declaration | ''Zeolite.h'' |
^ Implementation | ''Zeolite.cpp'' |

===== Function prototype =====

<code="C++">
void* zmap_GetScanlinePtr(ZMAP hMap, long j);
</code>

===== Arguments =====

^  Name  ^  Type  ^ Comment ^
|  //hMap//  |  ''ZMAP''  | A [[zeolite:types:ZMAP]] handle to a map. |
|  //j//  |  ''long''  | The y-axis coordinate of the scanline. Note the origin is at the southwest corner of the map. |

===== Return value =====

A null pointer if:
  * The map is not initialised, or;
  * The map is a mosaic (See ''[[zeolite:functions:zmap_GetMosaicFlag]]''), or;
  * An error occurred.
Otherwise, the return value is the pointer to the first pixel in the scanline. The number of pixels in the scanline is given by ''[[zeolite:functions:zmap_GetWidth]]'', and the type and size of the pixel data in the scanline may be retrieved from  ''[[zeolite:functions:zmap_GetMapType]]'' and ''[[zeolite:functions:zmap_GetPixelSize]]''.


===== Comments =====

None.